Tube-equipped, flanged, pressure transfer means of the technical field of the invention comprise: a flange for connecting the tube-equipped, flanged, pressure transfer structure to a tubular opening of a container or pipeline, which tubular opening is surrounded by a counterflange; a tube, which is secured, especially coaxially, to the flange and which protrudes from the plane of the flange, in order to protrude inwardly into the tubular opening; a hydraulic path, which extends from a first opening in a front end surface of the tube facing away from the flange, through the tube and through the flange, to a second opening in the rear end surface of the flange facing away from the tube; and an isolating diaphragm, which covers the first opening and is connected pressure-tightly with the front end surface of the tube along at least one peripheral edge, in order to form a pressure chamber between the isolating diaphragm and the front end surface of the tube, wherein the pressure chamber and the hydraulic path are filled with a pressure transfer liquid, in order to transfer a pressure presiding at the isolating diaphragm to the second opening.
Sense and purpose of the tube-equipped, flanged, pressure transfer structure is, for example, in the case of pressure measuring points arranged in so-called dished boiler ends, to assure that the isolating diaphragm is not so far back in a tubular flange connection relative to the surface of the dished boiler end that it is covered by thick sediments and thereby decoupled from the process to be monitored.
Tube-equipped, flanged, pressure transfer structure serve, especially in processes with large temperature differences relative to the environment, to bring the isolating diaphragm out of the plane of the flange and through the tubular opening, whose length often serves as a distance, over which the temperature can fall from that of the process to that of the environment, into a region of the pipeline or the container, in which there is no danger that, because of a temperature differing from that of the process, the isolating diaphragm is supplied with an incorrect pressure, or that process medium condenses or crystallizes on the isolating diaphragm. The length of the tube amounts, in such case, often to a number of diameters of the tubular opening.
Insofar as a condensation or crystallization of the medium is also to be prevented in the annular gap between the tube of the pressure transfer means and the tubular opening, it is usual that the tube fills the tubular opening as much as possible.
This requirement causes a relatively large volume for the tube and, associated therewith, a large mass, as is indicated, for example, in FIG. 4 for a tube-equipped, flanged, pressure transfer means 101 according to the state of the art. A flange 102 bears, in such case, a solid cylinder 104, on whose end an isolating diaphragm 110 encloses a pressure chamber, from which a bore 120 extends through the solid cylinder 104 to the rear-side of the flange, in order to transfer there the pressure presiding at the isolating diaphragm 110. Especially, tube-equipped, flanged, pressure transfer structure of corrosion resistant alloys are, therefore, very expensive. An approach for reducing the material expense is shown in FIG. 5, where, instead of a solid tube, a comparatively thin walled tube 204 is welded to the flange 202, wherein the hydraulic path between the separating diaphragm 210 and the rear-side of the flange 202 is then brought through the tube by means of a capillary line 220. The capillary line is then connected, on the one hand, with the flange 202 and, on the other hand, with a front end plate of the tube. The isolating diaphragm 210 is connected pressure-tightly to the front end place. This approach is burdened with high manufacturing risks.